1. Field of the Invention
This invention is directed to microscope optical component adjustment and, more particularly, to a device and method for assisting in the alignment of optical components in a microscope.
2. Description of the Related Art
A prior art optical microscope 10 is shown in FIG 1. The microscope contains a housing 12 which defines two optical paths; an illumination path 14 and an imaging path 16. The illumination path provides light to an objective lens 18 proximate a sample plane 22 containing a sample (not shown), and the imaging path 16 directs the image of the sample obtained by the objective lens 18 to an output port 31 containing, for example, an eyepiece, camera, or other capturing device 36. Disposed along the illumination path 14 are illumination components such as a set of lenses 24 and a set of apertures 26, and the imaging path 16 also contains a set of apertures 30 and a set of lenses 31. As shown, both paths converge on, or overlap to share, a common path region containing one or more optical elements including a beam splitter 34. The beam splitter directs the illumination light to the objective lens 18 and passes the resulting image to the output port 32 for processing, for example, by camera 36.
During microscope assembly as well as during microscope maintenance, the optical components must be aligned along their respective path positions relative to each other and relative to the sample plane 22 to insure proper microscope operation. The alignment and adjustment process is performed independently on each optical path with the use of an alignment telescope 29, which is typically first positioned at the illumination path input port 28 for directing a generated reference light beam along the illumination path 14 to the objective lens port 38 on the objective lens plane 20 defined on a surface of housing 12, i.e. to the plane where the objective lens mounts. The term xe2x80x9cobjective lens planexe2x80x9d is used herein to refer to a surface where the objective lens connects to the housing 12 and also defines a reference surface for an optical alignment target component. The objective lens 18 will not yet be in position in the lens port, as this positioning is typically performed after optical component alignment has been substantially completed. Instead, a target planar mirror having a cross-hair target (not shown) is placed in the objective lens port 38 for reflecting the reference light back through the illumination path 14 to the alignment telescope 29. Using the reflected light as a guide, the illumination path optical components are inserted on an element-by-element basis and manually manipulated for alignment along the illumination path 14.
Once alignment of the illumination path optical components is substantially complete, the alignment telescope is positioned at the imaging path output port 32 for directing the reference light to the target mirror along the imaging path 16. The imaging path optical components can then be installed on an element-by-element basis and aligned with respect to the target planar mirror position (i.e., at the objective lens port 38), such as by manual manipulation of the individual components. Thereafter, the objective lens 18 is substituted for the target mirror and is adjusted for tilt angle and centration with respect to a target sample (not shown) positioned on the sample plane 22. Once the objective lens 18 is adjusted, readjustment of the optical components in the illumination and imaging paths may be necessary for fine-tuning the alignment of those components.
A drawback of the prior art alignment technique discussed above is that the location of the target mirror at the sample planexe2x80x94which is used for adjustment of the objective lensxe2x80x94is different than the location of the target mirror at the objective lens port, i.e. the location used to align the illumination path and imaging path optical components. This not only requires adjustment of the objective lens after alignment of these other optical components but, the use of a different target location as a reference for the objective lens requires further fine-tuning, i.e. realignment and readjustment of the optical path components once the objective lens adjustment is completed. Thus, the alignment telescope 29 would be repositioned at the illumination path input port 28 for fine-tuning the illumination path optical components, and then repositioned at the imaging path port 32 for fine-tuning the imaging path optical components. Such a process is tedious and time consuming. Also, it may not be possible to know for certain which component is responsible for the misalignment, so a repetitive sequence of steps is required.
The aforementioned deficiencies of the prior art are overcome by providing a fixture configured for mounting to an objective lens plane of an optical microscope. The fixture includes a base having a mounting surface and an elongated wall or arm having an inner surface. The wall has at least one optical element reference mount for providing removable placement of a reference optical element along an optical path of the microscope. The fixture provides for alignment and adjustment of the microscope optical components, including an objective lens, relative to the reference optical element by positioning the reference optical element at a fixed distance from, and aligned with, the objective lens plane.
In one embodiment, the fixture contains multiple spaced apart mounts for accommodating varying types of reference optical elements for use in alignment techniques.
In another embodiment, a method of aligning optical components in a microscope is provided wherein a fixture having a base and a wall is positioned at an objective lens port of the microscope. An alignment beam is generated and is directed toward the objective lens port through the fixture base. A reference optical element is disposed within a path of the alignment beam for reflecting the alignment beam toward the alignment beam source. The reflected alignment beam is then used to align the optical components in the microscope relative to the reflected alignment beam.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.